Parquet floor coverings



April 29, 1969 R. E. BATAILLE: Y 3,440,787

PARQUET FLOOR COVERINGS Filed Jan. 13, 1967 @Mmmm Q@ @QQ/@mgm 1@ mp @aP Y H QQD@ @D @@QMQ@ @D 4@ @QQ CD Unted States Patent O 307 Int. Cl. E04f 13/08; l04b 5/00; E04c 2/04 I U.S. Cl. 52-390 5 Claims ABSTRACT OF THE DISCLOSURE The invention relates to the sound-proofing of parquet fioor coverings, particularly of mosaic type parquets made of juxtaposed parallel slats or fingers arranged in a square pattern, the slats or fingers of adjacent square elements being oriented at right angles to one another. The slats or fingers are separated from the underlying concrete slab by supporting elements formed by flat discs of sound insulating material having a thickness from 1.5 to 4 mm. and extending over a surface comprised between 30% and 50% of the total parquet area, said elements being bonded to the parquet ngers and to the concrete slabs by means of an appropriate adhesive.

This invention relates to improvements to parquet floor coverings and, more particularly, to the soundproofing of such coverings in order to reduce the transmission of noise which can reach excessively high levels due to the resonant nature of the reinforced concrete floor slabs used in modern buildings.

The invention applies in particular, though not exclusively, to oor coverings of parquet consisting of fingers, plaques or strips of wood, ceramic, or other material used for such purposes, one standard of the -dimensions of these fingers being 120 mm. long by 24 mm. wide. These fingers-as they will be called in the following description-are usually placed side by side to form a basic square, the side of which is equal to the length of the fingers: other patterns may however be adopted such as echelon or herring-bone arrangements. They are then preassembled; an acceptable architectural standard states that the method of preassembling the fingers must be of a temporary nature (e.g., paper facing), of sufiiciently flexible (e.g., thermoplastic net backing) to allow each individual finger sufiicient play after the panels have been laid.

The invention applies to parquets consisting of lingers in the nature of plaques or strips of other shapes and dimensions, or to analogous coverings consisting of wood or other materials.

It is already a known practice to place a layer of soundproofing material such as cork, between a concrete floor slab and a parquet covering. In such cases, one begins by sticking sheets of cork to the concrete slab, leaving sufficient gap between the edges of the sheets to allow for expansion. These sheets are then coated with adhesive on their exposed sides to which parquet panels, prepared as described above, are applied.

The results obtained with such a cork underlay are not very satisfactory: while tests of impact noise transmission show that, in relation to a parquet applied directly to the concrete, an appreciable improvement is obtained in the relatively high frequency range betweenV 1,600 and 3,200 Hertz, this improvement is not very significant (in the order of 6 to 12 decibels, according to the quality of the insulating sheet and of the adhesive used) in the case of medium frequencies between 400 to 1,200 Hertz, and is practically nil in the lower range of frequencies between 100 to 320 Hertz. Moreover, when rice this method is used, surplus adhesive may rise between the joints thus preventing the free relative movement of the wood fingers which constitutes the basic principle of parquet. In order to overcome this disadvantage, it has already been proposed that each wood finger be tted with a backing of some soundproofing material, for example a strip of cork to be stuck to the back of the finger, having dimensions slightly less in length and breadth than those of the finger itself so as to provide free spaces under the lateral and longitudinal joints between adjoining fingers. These free spaces can take up the surplus adhesive previously applied to the concrete slab.

It has also been proposed, to the same end, to stick multiple and identical backing pieces to the underside or rear face of the fingers. These backing pieces being rectangular in shape and having sides of dimensions slightly less than that of the width of the fingers and separated by a gap equal to the difference between the length and width of their shape, so as to form an underlay of cork with a network of channels of the same width. The channels so formed follow the longitudinal and transverse lines along which the fingers are placed. This fragmented arrangement of the cork underlay would appear to eliminate the difiiculties associated with the surplus adhesive, however, on the other hand, it procures no improvements whatever as regards soundproofing, particularly in respect of impact noise.

The floor covering which is the subject of this invention is intended to provide a remedy for the disadvantages described above and associated with present forms of soundproofing materials. It is characterized by the fact that the soundproofing backing consists of pieces or discs of material of small surface area which are distributed under the oor covering and have a total surface area of between 30% and 50% of that of the floor covering.

These components are just sufficiently thick, from 1.5 mm. to 4 mm. to avoid the possibility of resonance, so that when the oor covering is applied to the flooring slab, the rise of adhesive fills only part of the free space between the components.

The shape and positioning of these components ensure complete stability of the fingers whilst at the same time complying with architectural requirements applicable to parquet work. As the result of this arrangement, at least half of the surface area of the parquet is separated from the concrete slab by a free space which has a much better attenuating effect than cork, especially in the medium frequency range (400 to 1,250 Hertz) and the low frequency range to 320 Hertz), whilst at the same time it provides a substantial improvement in the high frequency range (1,600 to 3,200 Hertz).

Nevertheless, the ratio of the total area of the supporting components to the total area of the parquet is not very critical: for example, tests have shown that very similar results were obtained as regards the attenuation of noise throughout the whole range of frequencies when each wood finger, 24 by 120 mm., was supported either by 5 cork discs 16 mm. in diameter or by 4 discs 20 mm. in diameter, i.e., in respective proportions of 34% and 43% of cork surface in relation to the total surface area. (The thickness of the cork discs and the nature of the adhesive being the same in each case.)

On the other hand, for the same total surface area of the cork supporting components in proportion to the total area of the parquet, the degree of soundproofing varies according to the thickness of the discs.

In particular it has been found that coefficient a which characterises the improvement provided by the floor covering and takes into account the soundproofing in the three frequency ranges (low, medium and high) has a higher value in the case of discs 2 mm. thick than discs of 3 mm. and 4 mm. thick, the improvement being proportionately 4greater in the lower frequency range. This result is believed to be attributable to the fact that the free space between the concrete and the parquet may constitute a resonant chamber, thus the relationship between the free spaces and the wavelength of the sounds transmitted affects the degree of attenuation of these latter sounds.

Thus in the case of discs 2 mm. thick, 4 per finger of 24 by 120 mm., the following results were obtained in tests for levels of noise in decibels. The improvements recorded were in relation to bare concrete and for coefficient the figures relate to discs of 4 mm., 3 mm. and 2 mm. thick and the same bituminous adhesive was used in each case.

proofing material according to this invention is particularly economical as suitable cork discs are available as a commercial product. (In particular they are used in the manufacture of crown cork bottle tops, the quality of the cork used for these being suitable for soundproofing of parquets.) Consequently the cost of soundproofing according to this invention may be 40% to 50% lower than that of present methods. Other insulating materials such as synthetic materials may be used and the cost of manufacture, by moulding, could be very low due to the shape of the discs required.

In addition, the invention offers the advantage of allowing premanufacture of parquet panels of the kind referred to 48 cm. by 48 cm. or 24 cm. by 24 cm., which Low Medium High Noise Attenua- Noise Attenua- Noise Attenualevel tion level tion level tion in db. ln db. in db. in db. in db. in db. a

Discs (4 mm. thick) 64.3 3.3 57.3 13. 5 39. 2 32. 5 23 Discs (3 mm. thick) 63. 3 4. 3 57. 3 13. 5 37. 5 34. 2 24 Discs (2 mm. thick) 60. 5 7. l 55. 3 15. 5 34 37. 7 27 Thus it can be seen that the best coefficient a is obtained with discs 2 mm. thick.

It should be noted that the remarkable results shown in the above table depend in no way upon the adhesive employed. Thus, with a vinyl based adhesive, commonly used for laying parquet, the table below shows that, for a single thickness of disc, even better results were obtained.

Discs (3 mm. thick) By way of example, one form of parquet according to the invention is described below and illustrated :by the attached drawings.

FIGURE 1 is a plan view of the underside of a portion of panel.

FIGURE 2 is a sectional view of a linger in longitudinal elevation.

FIGURE 3 is a sectional view of a block of 5 fingers.

The parquet represented in the drawings consists of wood fingers, 1, 1', 1", 2, 2', 2", 3, 3', 3", which respectively form squares I, II, III with fingers placed at right angles so as to form a chequered pattern. These iingers are of standard dimensions, 24 by 120 mm., each having four discs 4, 4', 4" 4', with diameters of 20 mm. and spaced in such a manner as to keep the finger stable.

As may be seen in the drawing, the discs are disposed in such a manner that those at the extremities are about 2 mm. from the ends of the lingers, that is to say, the same distance as they are from the long sides of the fingers. The distance between the two inner discs 4' and 4" is less than that between these inner discs and those at the extremities 4 and 4', thus positioning discs 4' and 4" symmetrically in relation to the joints between fingers 3', 3" and 3"' of the adjoining square. The illustrated disposition of discs, which presents certain conveniences of manufacture, is by no means limiting and other dispositions compatible with mass production may be employed.

It is not necessary that all the discs should be identical, e.g., two mm. discs and three 16 mm. discs may be used etc. The essential is that the stability of the lingers and the ratio of the surface area of the discs to the lingers should be maintained.

It should be noted that parquet backed with soundare beforehand mounted on a pliable sublayer, preferably made of felt impregnated with pitch. As it has been noted that, when the fingers forming the parquet assembly are directly glued on such a sublayer, the expansion and the inflation of the wood resulting from an increase in the -atmospheric moisture will bring about, when the wood shrinks anew, the formation of gaps between the panels, reaching about 3 mm., as, at the expansion, the adjoining panels push back each other and the displacements of the panels add to each other, whereas the shrinking is carried on symmetrically with respect to the centers of the panels, thereby bringing along a separation. On the contrary, if the lingers according to the invention, provided with supporting cork disks are glued upon such a pliable sublayer, the cork disks will become deformed, absorbing the displacements which result from the expansion of the wood and will recover their initial shape when the wood contracts anew, so that the lingers will come back to their initial positions without the production of any gap between the premanufactured panels.

In addition, the gluing of the wood fingers upon the sublayer with a sufficiently resistant glue allows planing in the planing-mill, before the laying, whereas the panels are, for the present, laid down directly on flooring slabs made of concrete which are not perfectly smooth and are to be planed after the laying. The pliable sublayer absorbs the concrete irregularities and the planing after the laying is no longer necessary.

I claim:

1. A lioor covering consisting of a mosaic type parquet made of juxtaposed independent fingers and provided with supporting elements adherently fixed between each finger and an underlying concrete slab, said elements being formed by flat circular discs of sound insulating material secured to the under side of said fingers and having a diameter less than the width of the said fingers and a thickness of between 1.5 mm. and 4 mm., the total area of said supporting elements extending over a surface comprised between 30% and 50% of the area of the total floor covering.

2. A floor covering according to claim 1, in which said lingers comprise wooden fingers having 120 mm. length and 24 mm. width arranged in a group of square elements comprising live parallel fingers and the adjacent square elements being oriented at right angles to one another, each finger being provided at its under face with four discs of cork having a thickness of 2 mm. and a diameter of 20 mm.

3. A floor covering according to claim 1, in which said lingers comprise wooden fingers having mm. length and 24 mm. width arranged in a group of square elements comprising live parallel fingers and the adjacent square elements being oriented at right angles to one another, each nger being provided at its under face with References Cited a plurality of discs of cork each having a thickness of UNITED STATES PATENTS 2 mm. and a diameter of 16 mm.

4. A wooden finger for use in making up mosaic type 1,867,549 7/1932 Bmckmffyef 52-144 parquets having cork discs preixed to the under side 2,741,909 4/1956 Hlrtlmalr 52-384 thereof and adapted to be adherently fixed to the oor, 5 32272138 10/1966 Dlttmar 52-390 X said discs being separated from one another by free air 3:339325 9/1967 Knapp 52-390 X spaces `and having a thickness of between 1.5 mm. and FOREIGN PATENTS 4 mm., a diameter less than the width of the iinger, with the total area of said discs comprising between 30% 500071 2/1939 Great Bntam and 50% of the total area of the finger. 10 FRANK L ABBOTT P .m E

5. A floor covering according to claim 1, including a n ary rammen pliable sublayer made of pitch impregnated felt inter- PRICE C FAW, JR" ASSSIHH! Examinerposed between the concrete slab land the sound insulating discs being secured to the underside of the ingers U-S- C1- X-R and bonded to said subiayer. 15 52-4os, 48o, 603 

